Pharmacokinetic profile of Apravet® after oral administration

The objective of this study was to measure the concentrations of apramycin in the plasma and in the gastrointestinal tract during treatment with Apravet® and to determine the maintance of apramycin (APRM) after stopping the treatment.

Five groups of 4 pigs (Danube white), of both sexes (8.8-10.5 kg), 4-5 weeks of age, were used. On day 0 of the trial, four groups were treated via feed with 8 mg per kg bodyweight (BW) APRM as Apravet® 100 g/kg premix for 21 consecutive days. One group was not treated (Control group). Samples of the plasma, small intestinal content and large intestinal content were taken at day 21 (during treatment) and 12, 24, 36 and 48 hours after stopping the treatment. The evolution of concentrations of APRM was assessed applying HPLC determination in plasma and intestinal contents of pigs. the results of the examination were determined according to t-test of Student-Fisher.

The concentrations of APRM in the plasma (PC) and the small (SIC) and large intestinal (LIC) contents on day 21 were respectively 0.162 µg/ml and 45.0 and 88.2 µg/g. Twelve and 24 hours after the end of the treatment, the concentration remained high in the intestinal tract, respectively 33.2 and 10 µg/g (SIC) and 54 and 23 µg/g (LIC). The plasma concentrations quickly declined after 24 hours under LOQ (< 0.05). No statistically significant difference in APRM concentrations in small and large intestines were found, 12 hours after the treatment as compared to those found on the 21st day of the treatment. At all other time points APRM concentrations were statistically lower versus those found on the 21st day of the treatment

The results from the study show that Apravet® administration via feed at 8 mg per kg BW concentrates in small and large intestines which may have a significant role in establishing PK/PD relationships and clinical efficacy against bacterial enteritis in pigs. The present study highlights the maintenance of APRM concentrations in in the small and large intestines up to 36 hours after the 21st day of treatment. Until now, clinical breakpoints for apramycin used to treat bacterial enteritis were based upon aminoglycosides administered via parenteral route from other species. This study might help to better predict efficacy in vivo based upon in vitro susceptibility testing

Disclosure of Interest: None Declared.